1. Field of the Invention:
The present invention relates to an apparatus for measuring the amount of liquid vapor which is adsorbed or desorbed by a sample at various pressures. More specifically, the invention relates to an apparatus for measuring water vapor adsorption and desorption characteristics of porous materials and fine powder materials with fine particle sizes.
2. Brief Description of the Related Art:
In the characterization of porous materials and powder materials with fine particle sizes, the measurement of nitrogen adsorption-desorption isotherms for various pressures at the liquid nitrogen temperature is known. The analysis of the isotherms gives useful information about the pore structure, pore size distribution, surface area and porosity of the materials. Although the analysis of nitrogen adsorption-desorption characteristics is satisfactory for the analysis of many materials, other materials such as zeolites, clays, xerogels, catalysts, cements and ceramic powders, which are used in air or in humid atmosphere require analysis by adsorption-desorption isotherms of water vapor as well as nitrogen.